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136 lines
4.4 KiB
136 lines
4.4 KiB
/*
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* Distributed under the Boost Software License, Version 1.0.(See accompanying
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* file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt.)
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*
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* See http://www.boost.org/libs/iostreams for documentation.
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* File: boost/iostreams/detail/execute.hpp
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* Date: Thu Dec 06 13:21:54 MST 2007
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* Copyright: 2007-2008 CodeRage, LLC
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* Author: Jonathan Turkanis
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* Contact: turkanis at coderage dot com
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* Defines the overloaded function template
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* boost::iostreams::detail::execute_all() and the function template
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* boost::iostreams::detail::execute_foreach().
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*
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* execute_all() invokes a primary operation and performs a sequence of cleanup
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* operations, returning the result of the primary operation if no exceptions
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* are thrown. If one of the operations throws an exception, performs the
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* remaining operations and rethrows the initial exception.
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*
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* execute_foreach() is a variant of std::foreach which invokes a function
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* object for each item in a sequence, catching all execptions and rethrowing
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* the first caught exception after the function object has been invoked on each
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* item.
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*/
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#ifndef BOOST_IOSTREAMS_DETAIL_EXECUTE_HPP_INCLUDED
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#define BOOST_IOSTREAMS_DETAIL_EXECUTE_HPP_INCLUDED
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#if defined(_MSC_VER)
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# pragma once
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#endif
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#include <boost/config.hpp>
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#include <boost/detail/workaround.hpp>
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#include <boost/iostreams/detail/config/limits.hpp> // MAX_EXECUTE_ARITY
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#include <boost/preprocessor/arithmetic/dec.hpp>
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#include <boost/preprocessor/cat.hpp>
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#include <boost/preprocessor/iteration/local.hpp>
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#include <boost/preprocessor/repetition/enum_params.hpp>
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#include <boost/preprocessor/repetition/enum_binary_params.hpp>
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#include <boost/preprocessor/punctuation/comma_if.hpp>
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#include <boost/utility/result_of.hpp>
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namespace boost { namespace iostreams { namespace detail {
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// Helper for class template execute_traits.
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template<typename Result>
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struct execute_traits_impl {
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typedef Result result_type;
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template<typename Op>
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static Result execute(Op op) { return op(); }
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};
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// Specialization for void return. For simplicity, execute() returns int
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// for operations returning void. This could be avoided with additional work.
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template<>
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struct execute_traits_impl<void> {
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typedef int result_type;
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template<typename Op>
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static int execute(Op op) { op(); return 0; }
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};
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// Deduces the result type of Op and allows uniform treatment of operations
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// returning void and non-void.
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template< typename Op,
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typename Result = // VC6.5 workaround.
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#if !defined(BOOST_NO_RESULT_OF) && \
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!BOOST_WORKAROUND(__BORLANDC__, BOOST_TESTED_AT(0x592))
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typename boost::result_of<Op()>::type
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#else
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BOOST_DEDUCED_TYPENAME Op::result_type
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#endif
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>
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struct execute_traits
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: execute_traits_impl<Result>
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{ };
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// Implementation with no cleanup operations.
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template<typename Op>
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typename execute_traits<Op>::result_type
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execute_all(Op op)
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{
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return execute_traits<Op>::execute(op);
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}
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// Implementation with one or more cleanup operations
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#define BOOST_PP_LOCAL_MACRO(n) \
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template<typename Op, BOOST_PP_ENUM_PARAMS(n, typename C)> \
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typename execute_traits<Op>::result_type \
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execute_all(Op op, BOOST_PP_ENUM_BINARY_PARAMS(n, C, c)) \
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{ \
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typename execute_traits<Op>::result_type r; \
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try { \
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r = boost::iostreams::detail::execute_all( \
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op BOOST_PP_COMMA_IF(BOOST_PP_DEC(n)) \
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BOOST_PP_ENUM_PARAMS(BOOST_PP_DEC(n), c) \
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); \
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} catch (...) { \
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try { \
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BOOST_PP_CAT(c, BOOST_PP_DEC(n))(); \
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} catch (...) { } \
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throw; \
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} \
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BOOST_PP_CAT(c, BOOST_PP_DEC(n))(); \
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return r; \
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} \
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/**/
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#define BOOST_PP_LOCAL_LIMITS (1, BOOST_IOSTREAMS_MAX_EXECUTE_ARITY)
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#include BOOST_PP_LOCAL_ITERATE()
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#undef BOOST_PP_LOCAL_MACRO
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template<class InIt, class Op>
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Op execute_foreach(InIt first, InIt last, Op op)
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{
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if (first == last)
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return op;
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try {
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op(*first);
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} catch (...) {
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try {
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++first;
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boost::iostreams::detail::execute_foreach(first, last, op);
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} catch (...) { }
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throw;
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}
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++first;
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return boost::iostreams::detail::execute_foreach(first, last, op);
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}
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} } } // End namespaces detail, iostreams, boost.
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#endif // #ifndef BOOST_IOSTREAMS_DETAIL_EXECUTE_HPP_INCLUDED
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